1. Field of the Invention
This invention relates to a method for the production of a joint sintered article of high-temperature superconductive ceramics having particles oriented in different directions (direction of grain-orientation) across the interface thereof and to a joint sintered article produced by the method.
The present invention is utilized effectively in the development of such superconductive devices as superconductive magnetic sensors, superconductive transistors, and superconductive switches, for example.
2. Prior Art Statement
Superconductors possess such unusual properties as zero resistance, Josephson effect, and perfect diamagnetism. Owing to these unique phenomena, they are expected to encourage development of gigantic superconductive power generators and ultra high-speed computers. Since high-temperature superconductive ceramics manifesting superconductivity at temperatures above the temperature of liquefied nitrogen were discovered recently, the industrial application of such high-temperature superconductive ceramics has been spreading rapidly in the fields of electric power, electronics, transportation, and medicine, for example.
Recently reported high-temperature oxide superconductors exhibit their superconductive properties anisotropically by reason of crystal structure. This fact has led to the idea of developing new high-temperature superconductive devices which make use of interfaces across which the directions of grain-orientation are different.
Use of single crystals is conceivable as a means for producing superconductors possessing an interface across which directions of grain-orientation are different. As things stand now, high-temperature oxide superconductors are extremely limited in their ability to allow growth of single crystal. When a single crystal is obtained somehow or other, it has an extremely small size (on the order of several microns) and is sparingly capable of forming a joint interface of the foregoing description. While a thin film of superconductor may be formed in the shape of a single crystal on a substrate, it is difficult to join such thin films in such a manner that the directions of grain-orientation differ across the interface.
In the circumstances, the industry requires a technique for joining two oriented high-temperature superconductive ceramic masses in such a manner that their directions of grain-orientation differ across their interface and, at the same time, allowing the junction to maintain the superconductive properties of its own intact.